Osteochondritis dissecans

Introduction to exfoliative osteochondritis Most people think that this disease and traumatic osteochondral fracture or repeated mild trauma lead to blood circulation disorder, osteochondral necrosis caused by detachment, it is also suggested that bacterial embolism or fat embolization terminal artery and family inheritance, including debris and cartilage Bone underneath. There is a fibrous pedicle between the fragments and the mother bone or no pedicle free. The mother bone and the fragmentation surface are covered with fibrous tissue or fibrocartilage and a small amount of new bone formation, and the completely free body fragments are continuously increased by the absorption of synovial fluid by the free body. The size and number of free bodies can vary, and joint locks can occur. The pedicle fracture causes intra-articular hematoma, and joint wear produces proliferative arthritis. basic knowledge The proportion of illness: 0.002% Susceptible people: no specific people Mode of infection: non-infectious Complications: swelling, traumatic arthritis

The cause of exfoliative osteochondritis

Trauma (35%):

Direct trauma causes separation of bone and cartilage pieces, traumatic osteochondral fracture or repeated mild trauma leads to blood supply disorders, and osteochondral necrosis leads to the disease. Frequent, continuous trauma can cause damage to the bones and cartilage that cannot be repaired, causing osteochondral degeneration, exfoliation or dissociation.

Ischemia (20%)

Thrombosis or other pathological changes lead to local blood supply interruption, leading to regional osteonecrosis, separation of dead bone and articular cartilage covering it from healthy bone. Enneking found that the end of the subchondral artery had few anastomotic branches.

Other factors (20%):

Endocrine disorders or genetic factors, osteophyte embolism, infection, etc. are also associated with the disease.

Pathogenesis

The pathological anatomy of the disease mainly manifests as osteochondral damage in the joint. Clinically, the exfoliation of the osteochondral and the falling cartilage fall into the joint to form an intra-articular free body (which may also be in a semi-free state), resulting in joint dysfunction.

Exfoliative osteochondritis prevention

There is no effective preventive measure for this disease, but it should be noted that the patient's knee joint should be flexed by 30° after surgery for at least 6 weeks. During the braking period, the quadriceps are treated with equal length contraction. Activities are carried out early in order to restore the function of the affected limb as soon as possible.

Exfoliative osteochondritis complications Complications, swelling, traumatic arthritis

The early manifestations of this disease are intermittent dyskinesia, joint pain, swelling, effusion, joint stiffness, joint lock, etc., some patients can sometimes cause localized tenderness and muscle atrophy, exfoliative osteochondritis patients with advanced articular cartilage Fragmentation, local necrosis of bone resorption is replaced by fibrous tissue, shedding to form a free body, into the joint cavity to form joint mice, can also cause complications such as hematoma and traumatic arthritis.

Exfoliative osteochondritis symptoms Common symptoms Joint swelling Joint local tingling muscle atrophy Joint effusion Joint pain 2nd costal cartilage pain

The disease occurs in men between the ages of 16 and 25, knees, elbow joints are common, hip, shoulder, ankle or metatarsophalangeal joints are also visible, usually eroding a joint, no systemic symptoms, dull joint pain, increased activity The rest is relieved, the joints are swollen and light, and the free body may have joint lock, hematoma and traumatic arthritis. The joint swelling, effusion, tenderness, touching mass, limited activity can be heard, muscle atrophy, femur Internal hemorrhoids and external hemorrhoids, humeral articular surface, external iliac crest, humeral head, and talus of the ankle joint can be ill, which can lead to tenderness.

Exfoliative osteochondritis often occurs in the femoral condyle of the knee joint, which accounts for 85% (typically 69%, typical 6% extension, 10% lower central type), and external hemorrhoids account for 15%. % (13% for the lower center and 2% for the front type).

Staging of exfoliative osteochondritis:

Stage I: subchondral osteonecrosis, followed by secondary involvement of cartilage, the performance of articular cartilage is slightly softer.

Stage II: A portion of the articular surface, along with a small piece of cancellous bone under the cartilage, gradually necrosis due to ischemia and is separated from surrounding normal tissue.

Stage III: The cartilage is detached again, and the bones are sunken at the exfoliation. The bottom is attached with fibrous tissue. The edges are not uniform and are crater-like.

Exfoliative osteochondritis

There is no relevant laboratory examination. The auxiliary examination methods for this disease include X-ray examination, MRI examination and arthroscopy:

1X line inspection:

The typical injury is characterized by a clear outline of subchondral bone osteomalacia, which is separated from the surrounding normal bone. The fully exfoliated and displaced person can see the translucent defect area in the femoral condyle, and the free body can be seen in the joint cavity, although the X-ray examination is The use of this disease is more common, but the diagnostic value of plain film for OCD is very limited, because X-ray film can not directly display cartilage, and often miss small bone lesions or bone lesions that have not been stripped, that is, can not be found early The lesion is also not conducive to the staging of the lesion.

2. MRI examination:

MRI can display the knee anatomy in detail, especially the unique ability to directly display cartilage structure without angiography and the sensitivity to bone marrow lesions. It has become an effective method for early diagnosis of exfoliative osteochondritis and staging. MRI is non-invasive. It can clearly show the shape and signal changes of articular cartilage and subchondral bone.

3, arthroscopy:

Arthroscopic surgery, as a surgical method for minor trauma, has been considered as the "gold standard" for the evaluation of articular cartilage. However, in clinical use, arthroscopy and MRI have relatively insufficient deficiencies, and arthroscopy cannot detect it. Early osteochondral lesions without gross morphological changes, resulting in differences in MRI and arthroscopy, which is particularly prominent in type I OCD lesions. In addition, MRI can reflect the contour and thickness of cartilage surface, which is "arthroscopy" The status of the "gold standard" poses a challenge.

Diagnosis and identification of exfoliative osteochondritis

diagnosis:

The clinical symptoms of exfoliative osteochondritis are knee pain, repeated swelling or shackles. X-ray plain film: no obvious changes in early stage or subchondral bone ray-like absorption changes. Late visible femoral condyle has obvious bone. Absorption of necrosis or bone defect images, arthroscopy.

Differential diagnosis

1. Spontaneous osteonecrosis: occurs at the lower end of the femur. MRI shows a low signal in the necrotic area T1WI, and a high signal in the T2WI. The subchondral bone plate is generally uninterrupted. After the enhancement, the necrotic area can be uniformly enhanced, or it can be expressed in the periphery. Strip-like enhancement, the pathological basis of the fortified area is granulation tissue.

2. Osteoarthritis: At first, the articular cartilage is damaged first, and then new bone callus is formed at the edge of the articular cartilage. The bone hyperplasia and intraosseous cyst formation in the subchondral bone marrow may occur, and the hyperplasia of the synovial hyperplasia and the hardening of the subchondral bone may occur. On T1WI, T2WI showed a strip-like hardening zone with low signal in the subchondral bone marrow, and no exfoliation of bone fragments.

Clinically, it needs to be differentiated from bone erosion caused by rheumatoid arthritis, synovial osteochondroma disease, and pigmented villonodular synovitis, but the latter mainly focuses on soft tissue and synovial changes in the knee joint. .

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